The World Health Organization is warning Asian nations that its current struggle with bird flu could lead to the next deadly human flu pandemic across the globe. Millions could die. The WHO is holding a major regional conference in Bangkok this week to develop strategies to contain the flu and other infectious diseases.

The World Health Organization made an ominous prediction on Thursday that the current bout of bird flu in Asia could spark a deadly pandemic in humans.

During a conference on infectious disease in Bangkok, Klaus Stohr - who heads the WHO's Global Influenza Program - painted a grim picture of how a new and deadly human flu would affect the world.

"A pandemic will cause a public health emergency," he said. "There are estimates, which would put the number of deaths in the range of between two to seven million. The number of people affected would go beyond the billions."

Dr. Stohr says the world has not had a major flu pandemic in more than 30 years - way past the usual cycle. Recent findings that the 1918 flu pandemic, which killed 20 million people was cause by an animal flu virus, is sparking major concern among scientists.

The avian flu appears to have jumped to humans in Asia this year killing more than 30 people and leading to the slaughter of hundreds of millions of birds. Experts say efforts to contain the disease in birds are barely working.

Dr. Stohr also warns that while the H5N1 bird flu virus is worrying, other animal flu viruses circulating in Asia could also have pandemic potential.

"There's no doubt there will be another pandemic whether it is going to be happening this year or next year we don't know. Whether it is going to be H5N1 or another one we don't know," he said.

The WHO is urging countries to stock up on antiviral medications to help fight a possible flu outbreak.

Dr. Stohr, who spoke to scientists and officials from Southeast Asia, China, Japan and South Korea, says two U.S. companies are conducting trials on a bird flu vaccine - and one might be ready as early as March. Thai officials announced on Wednesday that their scientists could have a vaccine by 2007.

This is not the first time U.N. officials have sounded alarm at the possibility of a human flu pandemic. Last year Thailand initially covered up its avian flu outbreak at chicken farms, as poultry exports are central to the nation's agricultural sector.

The H5N1 strain of bird flu first jumped to humans in Hong Kong in 1997. It killed six of the eighteen people it infected.